body {
  background: url("bg.png") no-repeat center center fixed;
}
.container {
  width: 900px;
  margin: 0 auto;
}
.mask {
  display: none;
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.3);
  /* filter: blur(30); */
}
#sidebar_trigger {
  /*汉堡标签*/
  cursor: pointer;
  position: absolute;
  right: 30px;
  top: 30px;
  width: 30px;
  height: 5px;
  border-top: 15px double #fff;
  border-bottom: 5px solid #fff;
}
#sidebar {
  /* display: none; */
  position: fixed;
  top: 0;
  right: -300px;
  bottom: 0;
  width: 300px;
  background: #333;
  padding: 20px 0;
  transition: right 0.5s;
}
#sidebar ul {
  padding: 0;
  margin: 0;
  list-style: none;
}
#sidebar ul a {
  /* border: 1px solid red; */
  padding: 20px 50px;
  display: inline-block;
  text-decoration: none;
  color: #fff;
  width: 100%;
}
#sidebar ul a:hover {
  background: #444;
}



/* 新的代码重这里开始 */
.wrap {
  margin-top: 25px;
  /* border: 2px solid #fff; */
}
.diff {
  margin-top: 50px;
}
.wrap li {
  padding: 10px 80px;
  border-top: 2px solid #fff;
  border-left: 1px solid #fff;
  border-right: 1px solid #fff;
  border-bottom: 2px solid #fff;
  list-style: none;
}
.wrap li:first-child {
  border-left: 2px solid #fff;
}
.wrap li:last-child {
  border-right: 2px solid #fff;
}
.wrap li:hover {
  background-color: #fff;
}
.wrap li:hover a {
  color: #000;
  font-weight: bold;
}
.wrap ul {
  display: flex;
  /* justify-content: space-between; */
  justify-content: center;
}
li a {
  font-weight: bold;
  text-decoration: none;
  font-size: 20px;
  color: #fff;
}

/* 方法二  */

.wrap2{
  margin-top: 25px;
}
.wrap2 ul{
  display: flex;
  justify-content: center;
}
.wrap2 li{
  margin-left: -2px;
  padding: 10px 80px;
  border: 2px solid #fff;
  list-style: none;
}
.wrap2 li:hover {
  background-color: #fff;
}
.wrap2 li:hover a {
  color: #000;
  font-weight: bold;
}
.wrap2 div {
  margin-top: 30px;
}

